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2947 Views 2 Replies Latest reply: Feb 21, 2012 9:44 PM by Jordan Chernev RSS
Jeff Moore New Enzee
Jeff Moore
4 posts since
Dec 16, 2010
Currently Being Moderated

Feb 9, 2012 3:46 PM

Need help determining why a query is taking so long to write to spus

Hi,

 

1.  I have a query that returns data relatively quickly when run from the console and the output is redirected to dev/null.   I run the same query as a CTAS and distribute it on random and it is taking several orders of magnitude longer.  Thoughts on whay this might be happening?

 

2.  I've searched anaconda and every other doc I can find but have yet to find a good reference doc on using the nzsqa command.  Any one have a doc that would help me?

 

TIA

 

Jeff

Tags: nzsqa
  • Chris Rodgers Active Enzee
    Chris Rodgers
    185 posts since
    Sep 19, 2006
    Currently Being Moderated
    1. Feb 9, 2012 6:41 PM (in response to Jeff Moore)
    Re: Need help determining why a query is taking so long to write to spus

    How different are the plans (select versus CTAS)?  Explain plan info would be most helpful.  One explanation could be that your select is simply returning the data, but your CTAS may be redistributing data, causing the longer time to complete. Have you been able to reproduce the same issue?  If this is just one execution, you may be competing for resources on the box.  The plans are probably the best place to start.

  • Jordan Chernev Rookie
    Jordan Chernev
    183 posts since
    Jun 24, 2011
    Currently Being Moderated
    2. Feb 21, 2012 9:44 PM (in response to Chris Rodgers)
    Re: Need help determining why a query is taking so long to write to spus

    For question 2 - there a few KB articles on Netezza's support site but nothing really ground-breaking. I believe nzsqa is treated as more of an internal troubleshooting tool than an end-user utility.

     

    Some of the nice functionality that is provided by nzsqa is "nzsqa responders -sys" which can tell you how well you're spreading workload around the different SPUs. That being said, the same functionality is present in Aginity in a more-user friendly GUI format.

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